Post-Op Bypass Concerns*

WARNING: Unpleasant symptoms occurring after Obesity Surgery can indicate a progressing and/or life threatening problem that could require immediate hospitalization or surgery to control. Failure to notify the doctor immediately could result in preventable injury or death. Call 713-993-7124 IMMEDIATELY if untoward symptoms occur.

EARLY PROBLEMS (the first 7-10 days after surgery)

In general the first week after surgery is an important period to monitor for problems, as the majority of complications will occur during this time. Leak and bleeding, which are the most serious problems, tend to occur just after surgery and are less likely later in this period


This is the most common complication after Gastric Bypass and usually occurs within the first 24 hours. Typically, this is not fast bleeding at the time of surgery (although this can occur); rather it is usually from one of the reconnection points on the intestine or where the stomach has been divided. Approximately 1-2 % of patients who have Gastric Bypass will have significant bleeding requiring blood transfusion or extended hospital monitoring. Symptoms of blood loss are dizziness (especially on standing), shortness of breath, a rapid pulse (> 100 beats a minute), a pale appearance and minimal or no urine production. Of course, passing blood per rectum is diagnostic; however, this can be delayed 24-48 hours after staple line bleeding. Because bleeding is fairly common we require that all patients having Gastric Bypass stay overnight for observation.

Bowel Leak   

This is a life threatening complication. Fortunately, bowel leak after Gastric Bypass is rare, occurring in 1 out of 100–200 patients. It occurs when a hole or gap develops somewhere along the area of a Gastric Bypass allowing intestinal juice to escape into the abdominal cavity. A severe infection develops that can lead to sepsis (adverse symptoms involving all body systems) or septic shock (low blood pressure with injury to all body systems). Multiple Organ Failure can occur which is basically a shut down of many organ systems. With time this can lead to death.

Symptoms of bowel leak include: rapid heart rate, dizziness, shortness of breath, fever, worsening abdominal pain, abdominal distention, the appearance of illness and a general feeling that something is very wrong. Unfortunately, many of the symptoms may be absent or could be from something else (e.g. bleeding). Diagnosing a leak is further complicated by the fact that there is no single, reliable test to definitely diagnose a leak.

The diagnosis of a leak must be clinical, that is, the surgeon must consider all symptoms in relation to the timing after surgery. The diagnosis can never be 100% sure before treatment. If a leak is suspected the patient must go back to the operating room for an OPEN SURGERY to close the hole and clean up the leak. Usually, the patient will need to spend some time in the Intensive Care Unit (ICU) and rarely may require mechanical ventilation, temporary dialysis, and/or medications to support the blood pressure. Clearly, the key factor with a bowel leak is an early return to the operating room, even if the diagnosis is not assured.

Bowel Obstruction

This is an uncommon problem occurring in less than 1% of patients. The symptoms include nausea and vomiting, abdominal pain, abdominal distention and signs of dehydration (e.g. low urine production). Typically, the cause is a mechanical problem with the surgery, herniation of bowel into an incision site, or clogging of the intestine with clotted blood. Treatment is early re-operation which can be done laparoscopicaly, although conversion to open surgery might be necessary.

Blood Clots

This is a rare problem which occurs in less than 1% of patients. Obese patients are more prone to developing blood clots in the veins of the legs than are normal weight patients. The clot is dangerous because if it were to break off it might travel up the blood stream to the lung where is could suddenly decrease blood flow. This is known as a pulmonary embolism and frequently is fatal. The treatment is PREVENTION of the formation of blood clots. Our patients are given a short-acting blood thinner before surgery and sequential leg squeezing devices are fitted over the legs during the operation. Although, both of these are somewhat effective, neither is anywhere near as effective as the main treatment, which is getting out of bed and walking within 2 hours of the end of the operation. EARLY MOBILIZATION is the key to preventing blood clots. It is the most important thing the patient can do for him/herself around the time of the surgery.

Abdominal Abscess

This is a very rare problem if a bowel leak has not occurred first, probably occurring in 1 out of 300-500 patients. An abscess is a collection of pus localized to one area of the abdominal space (i.e. a contained infection). Symptoms include a rapid heart rate, fevers, and occasionally abdominal distention with or without vomiting. Usually, this will take longer to develop than a leak and will not progress as fast. An abscess can be diagnosed by CT scan and the treatment of choice is to have the radiologist place a drain into the cavity to drain the pus. Rarely re-operation will be required. The patient will need to stay in the hospital on antibiotics until the abscess clears.

Wound Infection

A wound infection is an infection of one of the incision sites, typically occurring 7-10 days after surgery. The incision will be red and warm, with thickening of the skin, sometimes accompanied by pus discharged from the wound. The patient may have fever. It should be noted that a small amount of redness along an incision is normal, and when this is not accompanied by the other signs is unlikely to be an infection. Treatment requires opening of the wound (to let the pus out), daily dressing changes of gauze to the wound base, and oral antibiotics. The patient will not need to stay in the hospital unless the infection is progressed or he/she has a vulnerability to infections (e.g. diabetes).

LONG TERM PROBLEMS (can occur any time after surgery)


A stenosis is a narrowing at one of the connection points – either the connection of the small pouch to the intestine or the “Y” connection of the bowel lower down. This problem occurs in about 1% of the patients, usually within several months of the surgery. It does not occur years later. A stenosis is basically an over-scarring at the connection which can decrease the size of the opening from approximately 1 cm in diameter to only a few millimeters. This means that the patient will not tolerate solid food, and, in some more extreme cases, will have difficulty with soft foods or even liquids. A classic indicator of a stenosis at the small pouch-intestine connection is a patient that tolerated solid food at one month after a gastric bypass, only to have problems with the same food sticking or causing vomiting several weeks later.

The treatment of a stenosis is to first diagnose the narrowing via an upper endoscopy. If a narrowing is seen a soft catheter with an inflatable balloon can be passed into the narrowed channel. By serially inflating the balloon the narrowed area can be dilated. This treatment is very effective and usually symptoms resolve after one dilatation.


The gastric bypass operation makes the patient more vulnerable for the formation of ulcers. These almost always occur in the small bowel just distal to the connection with the small gastric pouch, and are referred to as marginal ulcers. The stomach beyond the division from the small pouch is not at increased risk, and, may in fact, be less vulnerable to ulcer formation. Ulcer formation may occur in up to 5% of gastric bypass patients, frequently many months or years after the operation.

Several factors promote ulcer formation and make them harder to treat once they occur. Smoking may be the most single important factor. Smoking causes the small blood vessels in the inner lining of the small intestine to constrict, reducing blood flow to the cells in the lining. With less blood flow the cells become more vulnerable to injury and death which will eventually become an erosion or ulcer. Alcohol also makes the lining more easily injured. This effect is dose related with more alcohol causing a higher risk of ulceration. Non-steroidal anti-inflammatory medications (NSAIDs) such as Advil, Aleve, aspirin, Celebrex, ibuprofen, Motrin, naprosyn and Tylenol, among others, can lead to ulcers. This is of particular concern if a NSAID is taken at a maximum dose, around the clock, for several days. Finally, the bacterium Helicobacter Pylori – also known as H. Pylori – can make the bowel more vulnerable for ulcer formation. This chronic, low grade infection is very common, occurring in up to 25% of a regional population. Helicobacter pylori can be treated with a combination of oral antibiotics and a proton pump inhibitor (PPI). Recently, some antibiotic resistant strains of Helicobacter have been observed, requiring more than one course of treatment. Eradication of any of the factors cited above makes ulcers less likely to occur, or easier to treat once they do.

Rarely, an ulcer will become established prior to treatment or simply will not respond once treatment is initiated. A typical scenario is that where an ulcer has caused an element of obstruction from inflammation and narrowing of the connection between the small pouch and intestine. This leads to a blockage, and oral therapy can be less effective. And unlike a stenosis where the narrowing is short, the narrowed segment is longer and, therefore, does not respond to balloon dilatation. If the blockage is significant the area may need to be removed surgically and the pouch reconnected to the intestine lower down. This is known as revision of the gastro-jejunal anastamosis, and is required in approximately 1 of 200 patients who have had gastric bypass.

Bowel Obstruction

A bowel obstruction (blockage) can occur in any person who has had previous abdominal surgery, although it is more rare after laparoscopic than after open surgery. Gastric Bypass patients are at some higher level of risk due to the rearrangement of the intestine that is part of the operation. Several causes of bowel obstruction exist including adhesions (scars) inside the abdomen, internal hernia, abdominal wall (incisional) hernia, stenosis, ulcer inflammation, and intussusception (telescoping of the bowel). An internal hernia is a peculiarity which is fairly specific to the Gastric Bypass operation. Because of the rearrangement of the bowel several new defects are created in the supporting tissues, in which the bowel can later become trapped. Internal hernias are particularly difficult to diagnose prior to an operation. If the patient’s symptoms are suspicious for an internal hernia, then a laparoscopic examination inside the abdomen is warranted.

Although rare, the risk of bowel obstruction is life-long and could occur many years after Gastric Bypass. Therefore, any patient who is experiencing persistent vomiting and abdominal pain lasting more than a few hours, or who has an unexplained persistent pain – particularly in the left upper abdomen – should call the office immediately to be evaluated. Delay in treating a bowel obstruction can be dangerous.

Protein Deficiency

Generalized protein deficiency can occur in the first several months after Gastric Bypass during the time where weight loss is the most rapid. Low protein can lead to the depletion of many necessary body functions, and frequently results in the swelling of tissues, known as edema. Low protein is thought to contribute to increased hair loss sometimes seen after Gastric Bypass. We recommend protein supplementation for the first 6 months after Gastric Bypass to counter this problem. Whey protein supplements (protein powder) is favored over liquid protein supplements (protein shakes), because liquid calories are avoided. Ongoing protein depletion after 6 months does not occur, unless there is some other mechanical problem related to the surgery.

Vitamin and Mineral Deficiency

Vitamin B12

Vitamin B1 (thiamine)


Folic Acid


Please see the section on Vitamins and Minerals

IMPORTANT: The problems above are a partial list of all possible complications that can occur after this procedure. Some complications are rare and may be beyond the experience of the surgeon or even the surgical literature. Complications are usually not foreseeable.

WARNING: Unpleasant symptoms occurring after Obesity Surgery can indicate a progressing and/or life threatening problem that could require immediate hospitalization or surgery to control. Failure to notify the doctor immediately could result in preventable injury or death. Call 713-993-7124 IMMEDIATELY if untoward symptoms occur.

* Results will vary by person and are based upon the patient, the surgery type and the compliance with the aftercare program. As with any medical procedure or surgery, there are specific risks and possible complications. The testimonials, statements, and opinions presented on our website are applicable to the individuals depicted. Results may not be representative of the experience of others. Testimonials are voluntarily provided and are not paid, nor were they provided with free products, services, or any benefits in exchange for said statements. The testimonials are representative of patient experience but the exact number of pounds lost and experience will be unique and individual to each patient.

Make an appointment with Dr. Marvin for diagnosis and treatment.